Introduction. During the last two decades in criminalistics there have appeared many points of view and concepts that differ from the traditional ideas about the objectsubject area, tasks, system and language of this legal science. Among other things, the theoretical rethinking of the doctrine of forensic versions is being attempted. In particular, some discussion ideas about the partial reorientation of criminology from the tasks of fighting crime to specific spheres of human rights and other legal activities legal scholars make judgments about the need to study the versions put forward by the defence lawyer and other participants in criminal proceedings on the part of the defence. Such versions have different terminological designations and definitions in the legal literature. Some researchers make proposals on the possibility of attributing such assumptions to the number of forensic versions, as well as the development of forensic means and methods of their verification. Such proposals should be the subject of scientific analysis and discussion aimed at clarifying the essence and attributes of defence case as an object of forensic research. Methods. The methodological basis of the study was formed by general scientific and private scientific methods of cognition: dialectical, formal logic (analysis, synthesis, induction, deduction), historical, systemic, comparative study, hermeneutic and a number of others. Results. The analysis and critical review of legal scholars' views on the essence and attributes of versions formulated by participants of criminal proceedings on the part of the defence, as well as the scientific terminology used to designate such versions is carried out in the article. The author's definition of the defence versions is given and the discussion of the conclusions about the possibility of their attribution to the types of forensic versions is noted. The author concludes that defence case is an object of forensic research as an element of post-criminal activity of participants of criminal proceedings on the part of the defence. The tasks of evaluation and verification of defence versions during preliminary investigation and judicial investigation are given.